Generally, there are about 20,000 to 30,000 parts assembled in a vehicle. In particular, a plurality of panels for a door assembly are manufactured in a press process and then assembled with the door assembly by welding. Further, assembly quality of the door assembly is inspected to check quality of the door assembly which is assembled by the welding.
However, there is a need to move the door assembly from a moving jig to a test jig to inspect the assembled door assembly. In this case, the door assembly is not positioned in place causing a measurement error at the time of inspecting the assembling error, and instruments are thermally expanded or contracted depending on a temperature change causing the measurement error.